Patent Literature 1 discloses a method for the production of a lens for an optical scanning device used for a laser beam printer, a digital copying machine, or the like, the method comprising the steps of forming the lens by injection molding, measuring the shape of the surface of the molded lens, calculating shape errors by subtracting a design value (design shape) from a measured value (measured shape data), inverting the sign of the calculated shape error and superimposing it on the prior design shape as a correction amount, and producing a die for molding the lens.